Col José Luis Silva says he now recognises opposition leader Juan Guaidó as president instead.
Mr Guaidó declared himself "acting president" on Wednesday, gaining the backing of several countries including the US.
In response, Mr Maduro accused his rival of attempting a coup, and broke off relations with the US.
President Maduro was sworn in for a second term earlier this month after an election marred by an opposition boycott and allegations of vote-rigging, leading to large anti-Maduro protests.
More about: Venezuela
